The present invention relates to a storage system, and more specifically, to a storage system where the volume into which data is to be replicated can be selected.
In recent years, demand is increasing for shortening the time needed to replicate data stored in a storage device in a corporate storage system into another storage device for backup. This is primarily because less and less time is allocated for backup operation as the main corporate operation is getting longer, whereas more and more time is required to back up an increasing amount of data. To cope with such situations, an increasing number of companies have started using an arrangement where data to be backed up is replicated in a separate storage area or storage device. In such an arrangement, the data to be backed up is taken from the second storage area or storage device, while the main job stream continues using the first (original) storage area or storage device, so that the backup operation does not interfere with the main job stream.
Various interfaces are employed to connect a storage device to different pieces of computer equipment. Thus a storage device may be equipped with a Fibre Channel interface, the standardization of which is being promoted by the ANSI T11 committee (hereinafter called “FC storage device”), or with an AT Attachment (ATA) interface, the standardization of which is being promoted by the ANSI T13 committee (hereinafter called “ATA storage device”).
ATA storage devices are relatively inexpensive and are primarily used in desktop personal computers for home use. In contrast, FC storage devices are primarily used in corporate server systems since they have higher data input/output (I/O) performance than ATA storage devices and are reliable and robust enough to be employed in around-the-clock operation.
A storage system can also be constructed of different types of storage device so that it may use them for different purposes depending on the performance, costs, and other factors, as disclosed in the Laid-open Patent Specification No. Heisei 10 (1998)-301720, which provides a means of enhancing the reliability of data stored in a storage system.
Furthermore, as disclosed in the U.S. Pat. No. 5,434,992, an arrangement can be made such that in a storage system having different areas of cache for different types of data, the cache hit ratio is improved by optimizing the allocation of such cache areas.
In selecting a volume as the destination of replication in a storage system with storage devices having different characteristics or with a dividable cache, however, none of these inventions consider how well these characteristics of the destination candidates match the characteristics of the source volume. Also, these inventions are not specifically designed to relieve the user of the burden of selecting one out of a list of possible destination volumes, which tends to grow as the capacity of the storage system grows.